Telephone cable assemblies typically include multiple conductors terminated by modular plugs at ends thereof, the modular plugs having become standardized in such configuration as have jacks for releasable receipt of such plugs. Cables may comprise three, four or more pairs of conductors and the conductors are dedicated or preassigned in pairs. The plugs and jacks have contacts corresponding in number to the number of cable conductors and assigned likewise in pairs for communication purposes.
The cable plugs and associated telephone device jacks are mutually polarized, such that the cable assembly assigned pairs correspond on mating with circuitry connected to the jacks. All of this is seen also in the customary telephone set and associated cable in the average household. Given the jack and plug polarization, it is generally where errors exist in the cable or in its interconnection with its terminating plugs that error conditions exist in the telephone system.
As the art has long known, various errors can be present. Thus, the cable assembly conductors can be shorted to one another, individual cable assembly conductors or their terminations can be electrically discontinuous or open, or an individual cable assembly conductor pair can have its connections reversed at one end (polarity reversal within the pair).
Quite numerous varieties of telephone test apparatus are set forth in domestic and foreign patents and in commercial forms, such as is shown in the statement filed herein pursuant to 37 CFR 1.97 and 1.98. From applicants' viewpoint, such apparatus does not effect the required, known test functions in manner sufficiently expeditious to meet the needs of the industry.